Photovoltaic (PV) cells, commonly known as solar cells, are well known devices for direct conversion of solar radiation into electrical energy. Generally, solar cells are fabricated on a semiconductor wafer or substrate using semiconductor processing techniques to form a p-n junction near a surface of the substrate. Solar radiation impinging on the surface of, and entering into, the substrate creates electron and hole pairs in the bulk of the substrate. The electron and hole pairs migrate to p-doped and n-doped regions in the substrate, thereby generating a voltage differential between the doped regions. The doped regions are connected to conductive regions on the solar cell to direct an electrical current from the cell to an external circuit. Solar cells can be coupled together electrically (e.g., in series) to form a solar, or PV, module.
In operation, PV modules are exposed to the ambient atmosphere and can collect dust, dirt, or other particulates such that outer surfaces of the PV module become soiled. Soiled outer surfaces of the PV module can block solar radiation from reaching solar cells of the PV module, which can ultimately reduce the amount of energy produced by the PV module.